The weather in the Guianas is fairly constant year-round. Guyana, Suriname and French Guiana share the Atlantic coast of northern South America, all of it a few degrees north of the equator, and all three are warm, humid and tropical. The temperature barely moves from month to month. Rain is what changes, and rain is how the seasons are counted. For the bigger picture, start with our Guianas travel guide.
These are the official 1991–2020 climate normals from Guyana’s Hydrometeorological Service and Suriname’s Meteorological Service, as reported to the World Meteorological Organization, and from Météo-France for Cayenne. Highs and lows are the range of the monthly averages.
| City (weather station) | Typical high | Typical low | Rain per year | Wettest months | Driest months |
|---|---|---|---|---|---|
| Georgetown, Guyana (Botanical Gardens) | 85–89°F (30–32°C) | 71–74°F (22–24°C) | 90 in (2,281 mm) | May–July, December–January | September–October |
| Paramaribo, Suriname (Zorg en Hoop) | 84–90°F (29–32°C) | 74–77°F (23–25°C) | 84 in (2,136 mm) | May–June | September–October |
| Cayenne, French Guiana (Matoury) | 85–91°F (29–33°C) | 72–75°F (22–24°C) | 137 in (3,488 mm) | April–May | September–October |
| Lethem, Rupununi savanna, Guyana | 88–94°F (31–35°C) | 74–77°F (23–25°C) | 60 in (1,532 mm) | May–July | December–March |
On temperature the three capitals are close to twins. On rain they are not. Cayenne gets half as much again as Georgetown, and nearly 24 inches (600 mm) in May alone.
The coast has two wet seasons and two dry ones, though rain occurs year-round: even October, Georgetown’s driest month, brings 2.7 inches (69 mm) on about eight days. Each weather service draws the lines a little differently.
Guyana’s Hydrometeorological Service calls May to July the Long Wet Season. It builds through April, peaks in June (Georgetown’s wettest month, 11.9 inches or 303 mm) and eases from mid to late July. The long dry season runs from August into November, when the north turns wet again through January. February to April is dry once more.
Suriname keeps the same rhythm. Its Meteorological Service puts the short dry season at early February to mid-April, and the Dutch weather institute KNMI completes the year: the long rainy season through July, the long dry season from August to November and the short rainy season in December and January. In Paramaribo, May is the wettest month at 12.1 inches (307 mm), while September and October bring about 3.5 inches (87–90 mm) each.
Météo-France also counts four seasons, wetter ones. The short rainy season runs from December to mid-February. Then comes the petit été de mars, the “little summer of March”, a drier spell from mid-February to the end of March that varies a lot from year to year. The great rainy season is April to June, with May the wettest month at every climate station in the territory. The dry season lasts from July to the end of November, driest in September and October. Météo-France notes that hurricanes pass well clear of French Guiana without hitting it directly.
Typically, rainfall comes as heavy showers or thunderstorms. Nearly half of Cayenne’s 220 rainy days bring at least 0.4 inches (10 mm), and its thunderstorms peak in July. On the Guyana coast you’ll still get several hours of sunshine: Georgetown averages 5.5 hours a day in June, its cloudiest month, and 8 in October. French Guiana’s rainy season is greyer, with about 3 hours a day in Cayenne in February.
Which month suits which trip is a separate question, answered in the best time to visit the Guianas.
Further south, in the savannas towards Brazil, there is only one wet season. At Lethem, on the Rupununi savanna at the Brazilian border, the wet season runs from May to August: about 12 inches (293–310 mm) a month from May to July, tapering off in August. December to March is properly dry: January averages 0.6 inches (16 mm) on three days. From November to January, Hydromet notes, the north of Guyana is wet while the south stays dry.
Inland is hotter by day and no cooler at night. Lethem’s highs peak in October, and its lows sit slightly above Georgetown’s. French Guiana’s interior is similar: Maripasoula’s highs run 88–94°F (31–34°C), and Météo-France notes that inland the dry-season wind is very weak and the heat often heavy, with the odd thunderstorm for relief. Our Wild Guyana tour takes in Kaieteur, the Iwokrama rainforest and the Rupununi.
The coast is moderated by its winds. Georgetown’s monthly mean temperature sits at 80–83°F (27–28°C), and its highs stay a few degrees below Lethem’s. Météo-France describes French Guiana’s coast at the peak of the dry season as very dry but well ventilated, which keeps a lid on the heat.
Humidity is the part you feel. In Paramaribo the average relative humidity runs from 71% in September and October to 80% in June. September and October are also the hottest months on the coast. In October, Cayenne reaches 90°F (32°C) or more on about 25 days.
Some years stray far from these averages. Guyana’s Hydrometeorological Service and Météo-France both report that El Niño years tend to run drier and La Niña years wetter, in Guyana sometimes with flooding. If your trip falls in a strong El Niño or La Niña year, leave some slack in the plan.
Pack for heat and rain at once: light, quick-drying clothes, long sleeves for the evenings and the forest, a rain jacket or poncho, a hat and sunscreen. The full list is on our Guianas packing list, and for coping with heat and insects, see staying healthy in the Guianas.
If your route crosses several of these climates, share your dates when you ask about a custom Guianas trip, or look at our Three Guianas tour, which links Georgetown, Paramaribo and Cayenne along the coast.
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